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l008com · May 12, 2002, 01:56 PM

Is anyone else out there surprised that RC5 is still running? We've checked 77.143% of the keyspace and we haven't found the key yet. There is only a 22.857% chance that we would not have found the key by now...
Plus there are other organizations working on the RC5 challenge as well isn't there? That all just seems rather unlikely to me.

SkiBikeSki · May 12, 2002, 02:21 PM

I bet they put the winning key at a the end of the keyspace, just to test the worst case scenario. It seems like this wan't a challenge, since it is rather simple to find the right key, it just takes time. I think it was just a test to see how long it would take a very dedicated organization to systematically crack the 64bit encryption.

Shaktai · May 12, 2002, 02:25 PM

Originally posted by l008com:
Is anyone else out there surprised that RC5 is still running? We've checked 77.143% of the keyspace and we haven't found the key yet. There is only a 22.857% chance that we would not have found the key by now...
Plus there are other organizations working on the RC5 challenge as well isn't there? That all just seems rather unlikely to me.

Unexpected? Yes. Unlikely? maybe. Unusual? No 22.857% is still hundreds of Trillions of possibilities. It is merely random chance as to when the correct key is sent out. However, as the number of possibilities is diminished, your chance of finding the key increases. Remember, no matter how unlikely, there is always a possibility, that the correct key may be among the last .0001% of the keys sent out.

l008com · May 12, 2002, 02:25 PM

I disagree.... If anyone knew where they put the key, they'd get it and cash in. Even if we knew which part of the keyspace dnet was working on, which they keep quiet, we could then skip that part and work on the rest on our own and if we got it we could claim the $10,000 all to our selves.

** this was a reply to SkiBikeSki **

[ 05-12-2002: Message edited by: l008com ]

Grozni Majmun · May 12, 2002, 02:29 PM

Originally posted by l008com:
I disagree.... If anyone knew where they put the key, they'd get it and cash in. Even if we knew which part of the keyspace dnet was working on, which they keep quiet, we could then skip that part and work on the rest on our own and if we got it we could claim the $10,000 all to our selves.

I think it is $2000. Half to the team, half to the individual who finds the key. Then there's $8000 to a charity, but we'd never see that. Besides, we can't really decide which part of the keyspace to search, can we? I mean, we just have to crunch whatever they send out.

l008com · May 12, 2002, 02:35 PM

The challenge is being run by RSA, they are giving out a $10,000 to anyone who can find the key. Dnet is a whole separate entity, that has organized their own army of clients, and users, and they have divided up the keyspace their own way. If I find the key, that means they win, not me. And I get $2000 (no team). But if RSA 'put' the key at the end, then i'd devise my own method to check keys, starting at the end, so I could get the $10,000 all for my self.

SkiBikeSki · May 12, 2002, 03:19 PM

In case no one else noticed, dnet isn't giving out the keys in order. They're pretty much random. So the key could still be in the last unit given out, and there'd be no way to really predict which unit has the key.

Tigerabbit · May 13, 2002, 11:10 PM

Originally posted by l008com:
There is only a 22.857% chance that we would not have found the key by now...

It is only slightly less likely than flipping two coins and both landing tails (25%). It is slightly more likely than throwing two six-sided dice and the result being either 5 or 9 (22.222%). That's just the way the odds work out.

SkiBikeSki · May 14, 2002, 08:13 PM

To anyone who thinks they could figure out the key, and get the unknown message:

The actuall math involved in this type of secret-key cryptography is available to anyone who wants it. If you're good at math you might not even need to program anything, you could work it out with pencil and paper. However you'd better be very good at mods, exponents, logarithms, text-number conversion, atc... and not make any mistakes.

BTW The key itself could be as long as 20 digits in base 10. Not to mention the length of the other numbers you could be working with.

l008com · May 14, 2002, 08:16 PM

But it would still be a matter of trying random solutions right, and checking to see if you got the right one?
It sounds like fun I'm almost tempted to write my own client and applescript or something, sure it would be slow and it would never find the key, but it would be kinda cool

SkiBikeSki · May 14, 2002, 11:38 PM

Checking random random keys is just what the dnet RC5 client does. The only difference it that there are also 30,000 other poeple you're working with. And although the keys are given out randomly, the same key isn't given out twice, unless necessary.

Why write you're own client when you could just edit the source code of the dnetc client, to allow you to enter your our block of keys.

BTW Applescript is by no means capable of doin such complex math. The shear size of the number being using is too much for Applescript.